Which of the following numbers is a multiple of 2? ${61,77,79,85,90}$
Explanation: The multiples of $2$ are $2$ $4$ $6$ $8$ ..... In general, any number that leaves no remainder when divided by $2$ is considered a multiple of $2$ We can start by dividing each of our answer choices by $2$ $61 \div 2 = 30\text{ R }1$ $77 \div 2 = 38\text{ R }1$ $79 \div 2 = 39\text{ R }1$ $85 \div 2 = 42\text{ R }1$ $90 \div 2 = 45$ The only answer choice that leaves no remainder after the division is $90$ $ 45$ $2$ $90$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $2$ are contained within the prime factors of $90$ $90 = 2\times3\times3\times5 2 = 2$ Therefore the only multiple of $2$ out of our choices is $90$. We can say that $90$ is divisible by $2$.